Creating a Framework for Treating Autoimmune Gastritis-The Case for Replacing Lost Acid.

Autoimmune gastritis (AIG) is characterized by the destruction of gastric parietal cells, resulting in hypochlorhydria and eventual achlorhydria, as oxyntic glands in the corpus are destroyed and become atrophic. The permanent loss of gastric acid has many impacts-both theoretical and documented. The most concerning of these are hypergastrinemia and increased N-nitroso compounds, both of which increase the risk of gastric cancers. While known deficiencies of B12 and iron are often replaced in AIG, acid is not. Moreover, patients with AIG are often prescribed acid suppression for a stomach that is decidedly no longer acidic, worsening the sequelae of gastric atrophy. Betaine hydrochloride (BHCL) is a short-acting acidifying agent, available over the counter in capsule form. Mealtime acid supplementation has an historic basis and could ameliorate many AIG-related gastrointestinal symptoms. Theoretically, acidification could also reduce the potential for hypergastrinemia and the production of N-nitroso compounds, consequently reducing the risk of gastric cancers. Supplemental vitamin C may also help in preventing gastric N-nitroso formation, regardless of the gastric pH. This narrative review describes the functions of gastric acid in gastrointestinal and immune health, documents the effects of hypochlorhydria in AIG, and proposes potential options for safely re-establishing the acid milieu of the stomach for patients with AIG.

Deterioration of apatite orientation in the cholecystokinin B receptor gene (Cckbr)-deficient mouse femurs.

INTRODUCTION: The discrepancy between bone mineral density (BMD), the gold standard for bone assessment, and bone strength is a constraint in diagnosing bone function and determining treatment strategies for several bone diseases. Gastric hypochlorhydria induced by clinically used proton pump inhibitor (PPI) therapy indicates a discordance between changes in BMD and bone strength. Here, we used Cckbr-deficient mice with gastric hypochlorhydria to examine the effect of gastric hypochlorhydria on bone mass, BMD, and preferential orientation of the apatite crystallites, which is a strong indicator of bone strength. MATERIALS AND METHODS: Cckbr-deficient mice were created, and their femurs were analyzed for BMD and preferential orientation of the apatite c-axis along the femoral long axis. RESULTS: Cckbr-deficient mouse femurs displayed a slight osteoporotic bone loss at 18 weeks of age; however, BMD was comparable to that of wild-type mice. In contrast, apatite orientation in the femur mid-shaft significantly decreased from 9 to 18 weeks. To the best of our knowledge, this is the first report demonstrating the deterioration of apatite orientation in the bones of Cckbr-deficient mice. CONCLUSION: Lesions in Cckbr-deficient mice occurred earlier in apatite orientation than in bone mass. Hence, bone apatite orientation may be a promising method for detecting hypochlorhydria-induced osteoporosis caused by PPI treatment and warrants urgent clinical applications.

The occurrence, progression and development of four types of gastric mucosal atrophic lesions and their histopathological characteristics.

OBJECTIVE: To investigate the occurrence and development of gastric mucosal atrophic lesions and their histopathological characteristics. METHODS: Histopathological diagnosis and immunohistochemical staining using the EnVision two-step method were conducted on 1969 gastric mucosal atrophic lesions obtained from gastroscopic biopsy specimens. A total of 48-month three-stage endoscopic biopsy follow-ups were performed. RESULTS: When the gastric mucosal epithelium was affected by infection, chemical irritation, or immune or genetic factors, the gastric mucosal epithelium glands atrophied, the mucosa became thinner, the number of glands decreased, the intestinal epithelium progressed to metaplasia and smooth muscle fibre became hyperplasia. Such changes may lead to the proliferation and dysplasia of epithelial cells of the gastric mucosa and neoplastic hyperplasia in nature; this is referred to as gastric mucosal atrophic lesions in this study. According to this definition, the present study divided gastric mucosal atrophy into four types: (1) glandular atrophy of the lamina propria; (2) compensatory proliferative atrophy; (3) intestinal metaplasia atrophy; and (4) smooth muscle proliferative atrophy. The incidence rates of the above were 40.1% (789/1969), 14.3% (281/1969), 27.8% (547/1969) and 17.9% (352/1969), respectively. One- to 4-year follow-ups found that the changes were not significant and that the percentages of patients with disease exacerbation were 85.7% (1688/1969) and 9.8% (192/1969). The percentages of patients who developed low-grade intraepithelial neoplasia and high-grade intraepithelial neoplasia were 2.8% (55/1969) and 1.1% (21/1969), respectively; 0.7% (13/1969) of patients developed intramucosal cancer. CONCLUSION: Gastric mucosal atrophic lesions and histopathological staging are based on the morphological characteristics of gastric mucosal atrophy and the hypothesis of malignant transformation of cells during the occurrence and development of mucosal atrophy. Mastering pathological staging is beneficial to clinicians for enacting precise treatment and is important for reducing the incidence of gastric cancer.

Prediction of gastric pH-mediated drug exposure using physiologically-based pharmacokinetic modeling: A case study of itraconazole.

Abnormal gastric acidity, including achlorhydria, can act as a significant source of variability in orally administered drugs especially with pH-sensitive solubility profiles, such as weak bases, potentially resulting in an undesirable therapeutic response. This study aimed to evaluate the utility of physiologically-based pharmacokinetic (PBPK) modeling in the prediction of gastric pH-mediated drug exposure by using itraconazole, a weak base, as a case. An itraconazole PBPK model was developed on the mechanistic basis of its absorption kinetics in a middle-out manner from a stepwise in vitro-in vivo extrapolation to in vivo refinement. Afterward, an independent prospective clinical study evaluating gastric pH and itraconazole pharmacokinetics (PKs) under normal gastric acidity and esomeprazole-induced gastric hypoacidity was conducted for model validation. Validation was performed by comparing the predicted data with the clinical observations, and the valid model was subsequently applied to predict PK changes under achlorhydria. The developed itraconazole PBPK model showed reasonable reproducibility for gastric pH-mediated exposure observed in the clinical investigation. Based on the model-based simulations, itraconazole exposure was expected to be decreased up to 65% under achlorhydria, and furthermore, gastric pH-mediated exposure could be mechanistically interpreted according to sequential variation in total solubility, dissolution, and absorption. This study suggested the utility of PBPK modeling in the prediction of gastric pH-mediated exposure, especially for drugs whose absorption is susceptible to gastric pH. Our findings will serve as a leading model for further mechanistic assessment of exposure depending on gastric pH for various drugs, ultimately contributing to personalized pharmacotherapy.

Prevalence of achlorhydria in an Asian population detected using Congo red staining during routine gastroscopy: 22 years' experience from a single centre.

OBJECTIVE: We aimed to study the prevalence of achlorhydria (AC) in a large Asian population. DESIGN: Medical records of patients who underwent oesophagogastroduodenoscopy (OGD) with Congo red staining method at the Vichaiyut Hospital from January 2010 to December 2019 were retrospectively reviewed. RESULTS: A total of 3597 patients was recruited; 223 were excluded due to concurrent use of proton pump inhibitors. Eighteen from 3374 patients (0.53%) had AC. Seven patients were presented with permanent AC (5F, 2M) (median age=69 years; range 58-92). Among 11 patients with temporary AC (5M, 6F: mean age 73.4 years; SD 13.2 years), all had gastrointestinal Helicobacter pylori bacterial infection and were over 45 years old. After successful treatment for H. pylori, AC was absent among patients with temporary AC. If counting only patients over 45 years of age, the prevalence of AC was 0.68% (18/2614). No adverse events arising from Congo red occurred. CONCLUSION: AC is relatively rare. Permanent and temporary AC were found only when they were over 55 and 45 years old, respectively. Staining Congo red on gastric mucosa can be safely and routinely incorporated into the OGD procedure for early detection of AC. We recommended a low-cost screening test such as serum vitamin B levels for screening only in patients aged 50 and over.

Vitamin C Improves Dasatinib Concentrations Under Hypochlorhydric Conditions of the Simulated Stomach Duodenum Model.

PURPOSE: pH-dependent drug-drug interactions (DDIs) with poorly soluble, weakly basic drugs may lead to clinical implications. Dasatinib is a tyrosine kinase inhibitor with reduced absorption in patients on acid-reducing agents (ARAs). The objective of this study is to investigate the influence of gastric pH on dasatinib supersaturation and determine if vitamin C (L-ascorbic acid) can improve dasatinib concentrations under simulated hypochlorhydric gastric conditions. METHODS: A dynamic, in vitro, multi-compartment, simulated stomach duodenum (SSD) model mimicking fluid volumes and transfer rates was used to investigate the concentration of BCS class IIb drugs versus time curves. Dasatinib and lamotrigine were explored under normal, fasted, simulated gastric fluids (pH 2) (FaSGF), hypochlorhydric simulated gastric fluids (pH 4.5) (FaSGFhypo) and FaSGFhypo with 1000 mg of vitamin C. RESULTS: Significant supersaturation of dasatinib was observed in the duodenum compartment of the SSD model in FaSGF. A 90% reduction in dasatinib AUC∞ was observed in FaSGFhypo. Upon addition of vitamin C to FaSGFhypo, drug concentrations were restored to those observed in FaSGF. Lamotrigine AUC∞ in the duodenal compartment were similar in both FaSGF and FaSGFhypo. The in vitro trends observed for dasatinib and lamotrigine are reflective of the trends observed in vivo in subjects receiving treatment with ARAs. CONCLUSIONS: The SSD model serves as a good in vitro tool for assessing the effect of pH-dependent DDIs on bioavailability of weakly basic drugs with solubility/ dissolution limited absorption. Vitamin C provides a promising approach for improving bioavailability of poorly soluble, weakly basic drugs in hypochlorhydric patients.

The Potential Role of Hypochlorhydria in the Development of Duodenal Dysbiosis: A Preliminary Report.

In recent years, the role of gastric and duodenal microbiota has acquired increasing importance in the homeostasis of the host, although, to date, most evidence concern the faecal microbiota. Indeed, the gastric, and duodenal microbiota are challenging to study, due to gastric acid, bile, digestive enzymes, and rapid transit time. Specifically, the gastric acid environment may influence their bacterial composition since the acid barrier protects against orally ingested microorganisms and leads to their inactivation before reaching the intestine. The aim of this study was to assess a correlation between intragastric pH and gastric as well as intestinal microbiota of patients with histologic gastric alterations. pH was measured in the gastric juice and the bacterial composition in gastric and duodenal biopsies and faecal samples, was investigated via 16s rRNA gene sequencing. The main result is the direct correlation of duodenal microbiota biodiversity, via alpha diversity measures, with intragastric pH values. In particular, patients with hypochlorhydria showed increased duodenal microbiota biodiversity, higher intragastric pH values being prevalent in patients with chronic atrophic gastritis. Lastly, the latter was also strongly associated to the presence of oral bacteria, like Rothia mucilaginosa, Streptococcus salivarius and Granulicatella adiacens, in the duodenal microbiota. In conclusions, our results suggest a low-acid gastric environment as a contributive factor for duodenal dysbiosis, potentially leading to the development of pathological conditions of the gastrointestinal tract.

Parietal Cell Dysfunction: A Rare Cause of Gastric Neuroendocrine Neoplasm with Achlorhydria and Extreme Hypergastrinemia.

A 69-year-old woman with multiple neuroendocrine neoplasms (NENs) was referred to our hospital. Although she had extreme hypergastrinemia (11,675 pg/mL), no findings that indicated types I to III gastric NENs were found. Although gastric corpus atrophy was suspected on conventional white-light imaging, findings on magnifying endoscopy with narrow-band imaging indicated no severe atrophy. A biopsy from the background fundic gland mucosa revealed no atrophic changes, parietal cells with vacuolated cytoplasm and negative findings for H+K+-ATPase. Thus, this case was diagnosed as multiple NENs with parietal cell dysfunction. Neither progression nor metastasis has been confirmed during two-year follow-up.

Effect of gastrointestinal alterations mimicking elderly conditions on in vitro digestion of meat and soy proteins.

Among the physiological functions declining with aging, decreased secretion of gastric fluid, achlorhydria, is commonly observed. We evaluated the digestion of meat (chicken, beef, and pork) and soy proteins using in vitro conditions mimicking gastrointestinal (GI) digestion in adults (control, C) and elderly individuals with achlorhydria (EA). Changes in degrees of hydrolysis (DH), SDS-PAGE profiles, peptide concentrations, and proteomic profiles during digestion were investigated. Digestion under the EA conditions markedly decreased DH, especially for soy proteins. SDS-PAGE profiling and proteomics showed that myofibrillar/sarcoplasmic proteins from meat and glycinin/beta-conglycinin from soy were most affected by digestion conditions. Our results indicated that differences in the digestibility of meat protein between EA and control conditions gradually narrowed from the gastric to the intestinal phase for meat protein, while a pronounced difference persisted in the intestinal phase for soy protein. Our work provides new insight of value for future dietary recommendations for elderly individuals.

Helicobacter pylori infection and hypochlorhydria in Zambian adults and children: A secondary data analysis.

BACKGROUND: Hypochlorhydria (gastric pH >4) increases susceptibility to diarrhoea, iron deficiency, and gastric cancer. We sought to clarify the prevalence of this condition and its predisposing factors in Zambia by pooling data from previous studies conducted in hospital and community settings. METHODS: Gastric pH was measured in participants from five separate studies by collecting gastric aspirate from fasted adults and children under 3 years of age undergoing gastroscopy. Gastric pH was correlated with serological testing for Human Immunodeficiency Virus (HIV) and Helicobacter pylori (H. pylori) infections. RESULTS: We studied 597 individuals (487 adults and 110 children). Hypochlorhydria was present in 53% of adults and 31% of children. HIV infection was detected in 41% of adults and 11% of children. H. pylori serology was available for 366 individuals: 93% of adults and 6% of children were seropositive. In univariate analysis, hypochlorhydria was significantly associated with HIV seropositivity (OR 1.7; 95% CI 1.2-2.4; p = 0.004) and H. pylori antibody seropositivity (OR 4.9; 95% CI 2.8-8.6; p<0.0001), and with advancing age in HIV negative individuals (p = 0.0001). In multivariable analysis, only H. pylori was associated with hypochlorhydria (OR 4.0; 95% CI 2.2-7.2; p<0.0001) while excluding possible exposure to proton pump inhibitors. CONCLUSIONS: Hypochlorhydria is common in our population, with H. pylori being the dominant factor. Only young HIV seronegative individuals had a low prevalence of hypochlorhydria. This may have implications for the risk of other health conditions including gastric cancer.

Associations of atrophic gastritis and proton-pump inhibitor drug use with vitamin B-12 status, and the impact of fortified foods, in older adults.

BACKGROUND: Atrophic gastritis (AG) and use of proton pump inhibitors (PPIs) result in gastric acid suppression that can impair the absorption of vitamin B-12 from foods. The crystalline vitamin B-12 form, found in fortified foods, does not require gastric acid for its absorption and could thus be beneficial for older adults with hypochlorhydria, but evidence is lacking. OBJECTIVES: To investigate associations of AG and PPI use with vitamin B-12 status, and the potential protective role of fortified foods, in older adults. METHODS: Eligible participants (n = 3299) not using vitamin B-12 supplements were drawn from the Trinity-Ulster and Department of Agriculture cohort, a study of noninstitutionalized adults aged ≥60 y and recruited in 2008-2012. Vitamin B-12 status was measured using 4 biomarkers, and vitamin B-12 deficiency was defined as a combined indicator value < -0.5. A pepsinogen I:II ratio <3 was considered indicative of AG. RESULTS: AG was identified in 15% of participants and associated with significantly lower serum total vitamin B-12 (P < 0.001) and plasma holotranscobalamin (holoTC; P < 0.001), and higher prevalence of vitamin B-12 deficiency (38%), compared with PPI users (21%) and controls (without AG and nonusers of PPIs; 15%; P < 0.001). PPI drugs were used (≥6 mo) by 37% of participants and were associated with lower holoTC concentrations, but only in participants taking higher doses (≥30 mg/d). Regular, compared with nonregular, consumption of fortified foods (i.e., ≥5 and 0-4 portions/wk, respectively) was associated with higher vitamin B-12 biomarkers in all participants, but inadequate to restore normal vitamin B-12 status in those with AG. CONCLUSIONS: Older adults who have AG and/or use higher doses of PPIs are more likely to have indicators of vitamin B-12 deficiency. Fortified foods, if consumed regularly, were associated with enhanced vitamin B-12 status, but higher levels of added vitamin B-12 than currently provided could be warranted to optimize status in people with AG.

Gastric microbiota composition in patients with corpus atrophic gastritis.

BACKGROUND: In corpus atrophic gastritis (CAG), hypochlorhydria makes plausible the overgrowth of intragastric bacteria, whose role in gastric carcinogenesis is under debate. AIMS: To characterize the antrum/corpus composition of the gastric bacterial microbiota in CAG patients compared to controls without CAG. METHODS: A cross-sectional monocentric study on consecutive patients with known histological diagnosis of CAG undergoing gastroscopy for gastric cancer surveillance and patients without CAG undergoing gastroscopy for dyspepsia or anemia (108 biopsies from 55 patients, median age 61.5). Genomic DNA from one antral and one corpus biopsy from each case (n = 23) and control (n = 32) was extracted. Gastric microbiota was assessed by sequencing hypervariable regions of the 16SrRNA gene. RESULTS: Bacterial abundance and diversity were significantly lower in CAG cases than in controls (p < 0.001). Firmicutes were more frequent in cases, Bacteroidetes and Fusobacteria in controls (p < 0.0001). Streptococcaceae were more abundant in cases (p < 0.0001), Prevotellaceae in controls (p < 0.0001). The genus Streptococcus was positively correlated with severe OLGA/OLGIM stages linked to a higher risk of gastric cancer. CONCLUSION: Gastric bacterial microbiota in CAG showed a reduced abundance and complexity but was characterized by higher colonization of Firmicutes, in particular Streptococcus, increased in subjects with severe atrophy/metaplasia stages at higher risk of gastric cancer.

ACTIVITY OF SUPEROXIDE DISMUTASE AND CATALASE IN THE GASTRIC MUCOSA OF RATS UNDER THE PROLONGED ADMINISTRATION OF OMEPRAZOL AND COMBINATION OF OMEPRAZOLE AND MULTIPROBIOTICS.

OBJECTIVE: The aim: Of the study was to study the activity of superoxide dismutase and catalase in the gastric mucosa of rats under long-term administration of omeprazole and combined administration of omeprazole with Symbiter and Apibact multiprobiotics. PATIENTS AND METHODS: Materials and methods: The study was carried out on 40 white non-linear male rats with an initial weight of 160-180 g. All animals were divided into 4 groups. Group I was the control. Group II was administered omeprazole once a day within the period of 28 days. Group III was administered a combination of omeprazole and Symbiter® multiprobiotic. Group IV was administered a combination of omeprazole and Apibact® multiprobiotic. The activity of superoxide dismutase in cells was determined by Chevars et al. . The catalase activity in cells was determined by Korolyuk et al. . Statistical processing of the results was performed using the "Statistica 7.0" software. RESULTS: Results: The activity of SOD and catalase in the gastric mucosa of rats after 28 days of omeprazole administration increased compared to the control. Probiotics reduced the activity of SOD compared to the group of rats where omeprazole only was administered. The catalase activity in the gastric mucosa of rats which were jointly administered omeprazole and multiprobiotics for 28 days did not statistically significantly differ from the similar index in the control group. CONCLUSION: Conclusions: Prolonged gastric juice hypochlorhydria led to depletion of antioxidant protection enzymes. Multiprobiotics reduced the manifestation of the inflammatory process in the gastric mucosa.

Different elemental infant formulas show equivalent phosphorus and calcium bioavailability in healthy volunteers.

Retrospective chart reviews have reported hypophosphatemia associated with elemental formula use in infants and children with systemic disease involving multiple diagnoses. The present study aims to evaluate the bioavailability of phosphorus from 2 commercial elemental formulas and to test our hypothesis of bioequivalence of the 2 products in healthy volunteers receiving gastric acid-suppressive medication. A single-center, double-blind, randomized, cross-over study was conducted in healthy volunteers with esomeprazole-induced hypochlorhydria. After a standardized low phosphorus meal followed by overnight fasting, subjects consumed 1 gram of phosphorus in a single oral dose of 1217 kcal of Product A (Neocate) or Product B (Elecare). The alternate product was given following a 1-week washout period. Blood and urine were collected at baseline and different time-points for up to 6 hours after product consumption. Area-under-the-curve (AUC) and peak values (Cpeak) for serum phosphate and calcium and urinary creatinine-corrected phosphate and calcium were assessed for bioequivalence of Products A and B. Results show that the geometric mean ratio (GMR) and 90% CI for serum phosphate were 1.041 (0.998-1.086) and 1.020 (0.963-1.080) for AUC0-360 and Cpeak, respectively, meeting the predetermined criteria for bioequivalence. Urinary creatinine-corrected phosphate followed a similar pattern after intake of Product A and B, but did not reach bioequivalence criteria (GMR: AUC70-370 = 1.105 (0.918-1.330); Cpeak = 1.182 (1.040-1.343)). Serum calcium concentrations (GMR: AUC0-360 = 1.002 (0.996-1.009); Cpeak = 0.991 (0.983-0.999)) and urinary creatinine-corrected calcium excretion (GMR: AUC70-370 = 1.117 (1.023-1.219); Cpeak = 1.157 (1.073-1.247)) demonstrated bioequivalence of the products. In conclusion, both elemental infant formulas showed equivalent serum phosphorus and calcium bioavailability in healthy volunteers even if combined with treatment with acid-suppressive medication.

Common Pitfalls in the Management of Patients with Micronutrient Deficiency: Keep in Mind the Stomach.

Micronutrient deficiencies are relatively common, in particular iron and cobalamin deficiency, and may potentially lead to life-threatening clinical consequences when not promptly recognized and treated, especially in elderly patients. The stomach plays an important role in the homeostasis of some important hematopoietic micronutrients like iron and cobalamin, and probably in others equally important such as ascorbic acid, calcium, and magnesium. A key role is played by the corpus oxyntic mucosa composed of parietal cells whose main function is gastric acid secretion and intrinsic factor production. Gastric acid secretion is necessary for the digestion and absorption of cobalamin and the absorption of iron, calcium, and probably magnesium, and is also essential for the absorption, secretion, and activation of ascorbic acid. Several pathological conditions such as Helicobacter pylori-related gastritis, corpus atrophic gastritis, as well as antisecretory drugs, and gastric surgery may interfere with the normal functioning of gastric oxyntic mucosa and micronutrients homeostasis. Investigation of the stomach by gastroscopy plus biopsies should always be considered in the management of patients with micronutrient deficiencies. The current review focuses on the physiological and pathophysiological aspects of gastric acid secretion and the role of the stomach in iron, cobalamin, calcium, and magnesium deficiency and ascorbate homeostasis.

Gastric secretion in patients with caustic ingestion: A prospective study.

BACKGROUND: Caustic ingestion can lead to structural changes in the upper gastrointestinal tract. However, there are limited data on the effect of caustic ingestion on gastric secretion. This study was planned to determine the changes in gastric acid output in patients with caustic ingestion. METHODS: It was a prospective study done at a tertiary care center in northern India. Twenty consecutive patients in chronic phase of caustic ingestion were evaluated for the study. The gastric secretory function was estimated in the basal state and following pentagastrin stimulation. These results were compared with normal values for our laboratory. RESULTS: The mean age of the included patients (n = 20) was 27.35 ± 2.96 years and 14 patients were male. Sixteen (80%) patients had a history of acid ingestion. Patients with caustic ingestion had significantly lower mean gastric acid secretion (0.8 ± 0.4 mEq/h vs. 4 ± 0.4 mEq/h; p < 0.001) compared to controls. After pentagastrin stimulation, the mean gastric juice volume (31.8 ± 6 mL/h vs. 62.3 ± 11.7 mL/h; p < 0.01) and acidity (15.3 ± 5.1 mEq/L vs. 39.6 ± 9.3 mEq/L; p < 0.001) increased in patients with caustic ingestion, but were lower than those in control subjects. Patients with a lower esophageal stricture (n = 6) had decreased maximum acid output (0.62 ± 0.32 mEq/h vs. 6.05 ± 0.55 mEq/h; p < 0.05) compared to patients with stricture in the upper or middle esophagus. CONCLUSION: Caustic ingestion is associated with reduced gastric juice volume and acid output. Patients with stricture in the lower one third of the esophagus are at a higher risk of hypochlorhydria compared to patients with stricture in either the upper or middle esophagus.

Direct COVID-19 infection of enterocytes: The role of hypochlorhydria.

COVD-19 disease is characteristically respiratory in nature; however, some patients have gastrointestinal symptoms. These include changes in taste, nausea/vomiting, abdominal pain, and diarrhea. A report has been published of a young patient who repeatedly tested positive in stool samples while nasopharyngeal tests remained negative. This raises doubts about our understanding of the dynamics of COVID-19 disease. The current report describes a need for selective stool testing to explore fecal shedding of viral RNA and presents a hypothesis for direct infection of enterocytes in cases of hypochlorhydria.

Hypochlorhydria reduces mortality in heart failure caused by Kcne2 gene deletion.

Heart failure (HF) is an increasing global health crisis, affecting 40 million people and causing 50% mortality within 5 years of diagnosis. A fuller understanding of the genetic and environmental factors underlying HF, and novel therapeutic approaches to address it, are urgently warranted. Here, we discovered that cardiac-specific germline deletion in mice of potassium channel ß subunit-encoding Kcne2 (Kcne2CS-/- ) causes dilated cardiomyopathy and terminal HF (median longevity, 28 weeks). Mice with global Kcne2 deletion (Kcne2Glo-/- ) exhibit multiple HF risk factors, yet, paradoxically survived over twice as long as Kcne2CS-/- mice. Global Kcne2 deletion, which inhibits gastric acid secretion, reduced the relative abundance of species within Bacteroidales, a bacterial order that positively correlates with increased lifetime risk of human cardiovascular disease. Strikingly, the proton-pump inhibitor omeprazole similarly altered the microbiome and delayed terminal HF in Kcne2CS-/- mice, increasing survival 10-fold at 44 weeks. Thus, genetic or pharmacologic induction of hypochlorhydria and decreased gut Bacteroidales species are associated with lifespan extension in a novel HF model.